Generally, it is known that a ratchet wrench is a tool used for tightening or loosening a bolt or a nut. The ratchet wrench might be classified into various types depending on its size, type and use method.
In a conventional art, as shown in FIG. 1, a ratchet wrench comprises a body 10, a head unit 30 which is engaged at one side of the body 10 with a ratchet gear being attached to its outer rim, a handle unit 20 which is engaged at the other side of the body 10, and a socket 40 which is inserted into the head unit 30 and is equipped with a groove for receiving a bolt or a nut.
When it is needed to engage or disengaged a bolt or a nut by using a ratchet wrench, the handle unit 20 is rotated at a certain angle in one direction or in the other direction, and the head unit 30 and the socket 40 rotate, so the bolt head 50 inserted into the socket 40 rotates for thereby tightening or loosening the bolt.
However, since the socket of the conventional latchet wrench can be used only when engaging or disengaging the bolt of a single standard size, it should be disadvantageous that various different sizes sockets are used when engaging or disengaging different size sockets, which leads to many inconveniences in use.
When different size bolts are needed to be engaged or disengaged, a corresponding bolt is engaged or disengaged by using one ratchet wrench, and then the socket is disengaged from the head unit, and a new socket with a different size is engaged to the head unit for thereby engaging or disengaging a different size bolt. Whenever it is needed to engage or disengage the different size bolts, the socket should be changed with a corresponding size socket for thereby engaging and disengaging different size bolts, respectively.
Since it is needed to equip with multiple sockets for different size bolts, a lot of cost is needed, and a heavy toolbox is needed for storing the different size bolts. In the conventional art, it is impossible to engage or disengage a bolt or a nut disposed in a deep groove of a work object.